The British Medical Journal Case Reports chronicled the medical case of the woman, who has not been identified, was sent to a GI specialist after various symptoms, including weight loss. When doctors scanned the woman's intestinal tract, they discovered, "A linear foreign body in the stomach." After the discovery, the woman said she remembered accidentally swallowing a black felt-tip pen, more than a quarter century ago.

While the pen was corroded after two decades of exposure to stomach acid, it still contained usable ink and could be used for writing.

More from the report by Dr. Oliver Richard Waters:

While she was interrogating a spot on her tonsil with the pen she slipped, fell and swallowed the pen by mistake. Her husband and general practitioner dismissed her story and plain abdominal films done at the time were reported as normal. A gastroscopy demonstrated a plastic felt-tip pen sitting in the lumen of the stomach without evidence of any gastric damage.

Even though the pen was apparently not related to the woman's current health issues, doctors went ahead and removed it anyway. In perhaps a bit of dry humor, Dr. Waters concluded in his report:

This case highlights that plain abdominal x-rays may not identify ingested plastic objects and occasionally it may be worth believing the patient's account however unlikely it may be.